VR probably has a higher per capita usage among kids than 30 year olds to be fair. My first graphics card was bequeathed to me at the tender age of 11 back when GPUs were a niche thing

>How many kids (using a large range from ages 1-18) have VR setups in their homes?

Can't answer this directly but recently the multiplayer VR games have had more 10-16 year olds than any other group

You can play recroom with an Oculus Quest, PSVR, or regular screen if you want. The Quest 2 base model costs $300 and is entirely standalone, no PC required.

I have a Valve Index ($1,000 + gaming PC + installing 2 lighthouses on my walls), and while my experience is definitely better (other than the cord), the Quest provides a comparable experience for beat saber, rec room, pistol whip, which comprise 90% of what I use my Index for anyway.

It's probably going to change soon. You can buy a Quest 2 for the same price as a Nintendo switch now. It doesn't need an accompanying gaming pc.

Kids will be getting their dad's (or mom's) hand me down VR system within a few years when those parents eventually choose to upgrade.

Quest 2 is $299, that's a barrier but not insane. Also, Rec Room is not VR only, there are clients for iOS, PC and PS4 that run in a mode with no VR (obviously VR isn't even an option for iOS). That's not as much platform coverage as Roblox, but it's not bad. Definitely worth checking out even if you don't have VR.